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Manage Certificates With Cert Manager

This tutorial will detail how to manage secrets of ApisixTls using cert-manager.

Prerequisites#

In this guide, we assume that your APISIX is installed with ssl enabled, which is not enabled by default in the Helm Chart. To enable it, you need to set apisix.ssl.enabled=true during installation.

For example, you could install APISIX and APISIX ingress controller by running:

#  We use Apisix 3.0 in this example. If you're using Apisix v2.x, please set to v2
ADMIN_API_VERSION=v3
helm install apisix apisix/apisix \
  --set service.type=NodePort \
  --set ingress-controller.enabled=true \
  --set apisix.ssl.enabled=true \
  --set ingress-controller.config.apisix.serviceNamespace=default \
  --set ingress-controller.config.apisix.adminAPIVersion=$ADMIN_API_VERSION

Assume that the SSL port is 9443.

Create Issuer#

For testing purposes, we will use a simple CA issuer. All required files can be found here.

To create a CA issuer, use the following commands:

kubectl apply -f ./cert-manager/ca.yaml
kubectl apply -f ./cert-manager/issuer.yaml

If the cert-manager is working correctly, we should be able to see the Ready status by running:

kubectl get issuer

It should output:

NAME        READY   AGE
ca-issuer   True    50s

Create Certificate#

Before creating ApisixTls, we should create a Certificate resource.

apiVersion: cert-manager.io/v1
kind: Certificate
metadata:
  name: demo-cert
spec:
  dnsNames:
    - local.httpbin.org
  issuerRef:
    kind: Issuer
    name: ca-issuer
  secretName: example-cert
  usages:
    - digital signature
    - key encipherment
  renewBefore: 0h55m0s
  duration: 1h0m0s

Note that we set the parameters duration and renewBefore. We want to test if the certificate rotation functionality is working well, so a shorter renewal time will help.

Like Issuer, we could see its readiness status by running:

kubectl get certificate

It should output:

NAME        READY   SECRET        AGE
demo-cert   True    example-cert  50s

Check the secrets by running:

kubectl get secret

It should output:

NAME          TYPE                DATA   AGE
example-cert  kubernetes.io/tls   3      2m20s

This means that our cert-manager is working properly.

Create Test Service#

We use kennethreitz/httpbin as the service image.

Deploy it by running:

kubectl run httpbin --image kennethreitz/httpbin --expose --port 80

Route the Service#

Create an ApisixRoute to route the service:

apiVersion: apisix.apache.org/v2
kind: ApisixRoute
metadata:
  name: httpserver-route
spec:
  http:
    - name: httpbin
      match:
        hosts:
          - local.httpbin.org
        paths:
          - "/*"
      backends:
        - serviceName: httpbin
          servicePort: 80

Run curl command in a APISIX pod to see if the routing configuration works.

kubectl -n <APISIX_NAMESPACE> exec -it <APISIX_POD_NAME> -- curl http://127.0.0.1:9080/ip -H 'Host: local.httpbin.org'

It should output:

{
  "origin": "127.0.0.1"
}

Secure the Route#

Create an ApisixTls to secure the route, referring to the secret created by cert-manager:

apiVersion: apisix.apache.org/v2
kind: ApisixTls
metadata:
  name: example-tls
spec:
  hosts:
    - local.httpbin.org
  secret:
    name: example-cert # the secret created by cert-manager
    namespace: default # secret namespace

Run curl command in a APISIX pod to see if the Ingress and TLS configuration are working.

kubectl -n <APISIX_NAMESPACE> exec -it <APISIX_POD_NAME> -- curl --resolve 'local.httpbin.org:9443:127.0.0.1' "https://local.httpbin.org:9443/ip" -k

It should output:

{
  "origin": "127.0.0.1"
}

Test Certificate Rotation#

To verify certificate rotation, we can add a verbose parameter -v to curl command:

kubectl -n <APISIX_NAMESPACE> exec -it <APISIX_POD_NAME> -- curl --resolve 'local.httpbin.org:9443:127.0.0.1' "https://local.httpbin.org:9443/ip" -k -v

The verbose option will show us the handshake log, which also contains the certificate information.

Example output:

* Added local.httpbin.org:9443:127.0.0.1 to DNS cache
* Hostname local.httpbin.org was found in DNS cache
*   Trying 127.0.0.1:9443...
* Connected to local.httpbin.org (127.0.0.1) port 9443 (#0)
...
...
* Server certificate:
*  subject: [NONE]
*  start date: Sep 16 00:14:55 2021 GMT
*  expire date: Sep 16 01:14:55 2021 GMT
*  issuer: C=CN; ST=Zhejiang; L=Hangzhou; O=APISIX-Test-CA_; OU=APISIX_CA_ROOT_; CN=APISIX.ROOT_; emailAddress=test@test.com

We could see the start date and expiration date of the server certificate.

Since the Certificate we defined requires the cert-manager to renew the cert every 5 minutes, we should be able to see the changes to the server certificate after 5 minutes.

* Added local.httpbin.org:9443:127.0.0.1 to DNS cache
* Hostname local.httpbin.org was found in DNS cache
*   Trying 127.0.0.1:9443...
* Connected to local.httpbin.org (127.0.0.1) port 9443 (#0)
...
...
* Server certificate:
*  subject: [NONE]
*  start date: Sep 16 00:19:55 2021 GMT
*  expire date: Sep 16 01:19:55 2021 GMT
*  issuer: C=CN; ST=Zhejiang; L=Hangzhou; O=APISIX-Test-CA_; OU=APISIX_CA_ROOT_; CN=APISIX.ROOT_; emailAddress=test@test.com

The certificate was rotated as expected.